The world must judge Iran's intentions by its actions and not by its "presentations" at the latest talks on its disputed nuclear programme, a senior Israeli official said Thursday.

"Iran will be judged by its actions and not by its presentations," the official said on condition of anonymity, in remarks just hours after world powers wrapped up two days of talks which the United States described as showing a new level of "seriousness".

But Israel was quick to pour water on the upbeat tone emanating from Geneva, where the talks were held on Tuesday and Wednesday.

"Until significant steps are carried out on the ground which prove that Iran is breaking up its military nuclear programme, the international community must continue to impose sanctions upon it," he said, reiterating a line repeatedly driven home by top Israeli officials in recent weeks.

"The pressure of sanctions brought Iran to this point and must continue until Iran is stripped of its nuclear military programme," he concluded.

As the negotiations drew to a close on yesterday, both Washington and Tehran took a positive tone, with Iran saying it was hopeful for a "new phase in our relations" with world, and the White House saying the Islamic republic had shown a greater level of "seriousness and substance" than ever before.

At the talks, Iran outlined a three-step plan which it said could settle the nuclear dispute "within a year", and it also made a "breakthrough" proposal to allow spot checks on its nuclear sites.

The next meeting between Iran and the so-called P5+1 group of world powers will take place in Geneva on November 7 and 8.